[shorod]

Are you sure you're looking at the A/C compressor and not the alternator when you say there are 4-wires going into the back? I'll have to check my service manual tonight, but if there are four wires going to the back, two of them have to make it to the front to engage the clutch field coil and I'm not sure what the other two would go to.

And to properly check the level of the R-134a refrigerant, you'll need a set of appropriate gauges.

-Rod